1. Field of the Invention
The present invention relates to a plasma processing apparatus or a plasma processing method that performs processing to a sample on a substrate, such as a semiconductor wafer, disposed in a processing chamber inside a vacuum chamber using plasma formed in the processing chamber. More specifically, the invention relates to a plasma processing apparatus or a plasma processing method that detects progress of processing by using light acquired from a film structure during the processing to a film layer to be processed of the film structure including a plurality of film layers previously disposed on a surface of the sample.
2. Description of the Related Art
In the related art, the following technique for the above plasma processing apparatus or plasma processing method, has been known. During processing, such as etching of a film structure to be processed, a film to be processed is etched and then a film layer including a different material disposed on the under the film layer is exposed. As a result, intensity or a change of the intensity of light emission of a predetermined wavelength caused from plasma is detected so as to detect an end point of the processing.
In a case where etching processing is performed to a film to be processed so that the film has desired film thickness or desired depth from a surface, the following technique has been known. Intensity of interference light including a plurality of wavelengths from a surface of a sample or a change with respect to a temporal change of a rate of change of the intensity, is detected from a top of the sample, such as a wafer, during processing. Then, time series data of the interference light including the plurality of wavelengths is compared to database that has been previously acquired so as to detect film thickness or depth of the film to be processed. As the above technique in the related art, for example, a technique disclosed in JP-2003-83720-A has been known.